Inside surface of a filter element having insert construction

FIG. 1 is a perspective view of the inside surface of a filter element having an insert construction showing our new design. This particular perspective view is not normally viewable through the side walls of the filter element, but is illustrated for purposes of clarity.

FIG. 2 is a top plan view thererof; and,

FIG. 3 is a side elevational view thereof, all the sides being identical. This particular side elevational view is not normally viewable through the side walls of the filter element, but us illustrated for purposes of clarity.

The broken lines which define the bounds of the claimed design form no part thereof. The broken line environmental showing is for illustrative purposes only and forms no part of the claimed design.